incertus

Incertus is a Latin adjective meaning uncertain, doubtful, or wavering. It derives from the negative prefix in- combined with certus, “certain,” and has been used since classical times to describe lack of certainty in persons, statements, or classifications. The word appears in masculine, feminine, and neuter forms (incertus, incerta, incertum), with corresponding grammatical endings.

In taxonomy and systematics, incertus commonly appears in the phrase incertae sedis, meaning “of uncertain position.” This conventional label is applied to taxa whose broader placement within a family or higher group is unresolved. The expression signals that a taxon’s relationships are unknown or disputed, pending further study or data. While incertae sedis is the principal way the concept is conveyed today, historical usage sometimes employed nominal forms or phrases indicating uncertainty about classification.

In textual criticism, manuscript studies, and historical scholarship, incertus is used to flag uncertain aspects such as authorship, date, provenance, or readings of a text. Editors may note passages as incertus to reflect doubts about attribution or authenticity, guiding readers toward caution in interpretation.

Beyond taxonomy and textual work, incertus has appeared in philosophical and scholastic writing to describe propositions, authors, or claims judged as not yet established or fully proven. In modern usage, Latin terms related to uncertainty, including incertus and incertae sedis, remain common in scholarly discourse as concise indicators of unresolved questions.